The field of the invention relates generally to wheel balancers and more specifically to wheel balancers configured to measure tire uniformity parameters and to alter tire uniformity parameters with tire bead seat massaging.
Much attention has been directed to problems associated with vibration issues in wheel assemblies consisting of a wheel rim and an associated tire mounted thereon. Techniques have been developed to detect wheel assembly combinations that are likely to cause such vibration issues, as well as to reduce or mitigate such vibration issues in a wheel assembly. Towards this end, wheel balancers are configured to reduce static and dynamic imbalances in a wheel assembly. Wheel balancer systems typically determine a measure of imbalance in a wheel assembly by an analysis of the mechanical vibrations resulting from rotation of the wheel assembly about an axis of a supporting spindle shaft. The mechanical vibrations are measured as motions, forces, or pressures by means of sensors such as transducers, which convert the mechanical vibrations into electrical signals. Wheel assembly imbalance may result from imbalance in the wheel rim, imbalance in the tire, or both. The wheel rims and tires may be rotated to relative positions with respect to one another to minimize vibrations, and correction weights may be applied to counteract unbalance forces in the wheel assembly to reduce measured vibrations to acceptable levels.
Even when properly balanced, non-uniformity in the construction of the tire or a runout in the wheel rim can cause significant vibration forces as the wheel assembly rolls across a road surface under vehicle load conditions. While most tire manufacturers inspect their tires on tire uniformity machines and grind surface material off the tires to remove non-uniformities in order to improve the rolling characteristics of the tires, the tires may still produce significant vibration forces that are unrelated to an imbalance of the wheel assembly as they roll on a smooth road. The reasons for this can be somewhat complex, and wheel balancer systems can, as a result, be quite sophisticated in addressing them.
A vehicle service provider that utilizes both a wheel balancer and a tire changer machine can effectively solve most vibration issues found in wheel assemblies. Following a tire changing procedure for the wheel assembly completed on a tire changer machine, the wheel assembly is analyzed with a wheel balancer to identify and correct imbalances. Finally, the wheel assembly is mounted to the vehicle for use. In some instances, the use of both a wheel balancer and a tire changer machine in such a manner results in an inefficient process for new tire installation. If a vibration issue is detected or predicted, but not solved, on the wheel balancer, the mounting arrangement of the wheel rim and tire must be altered by returning the wheel assembly to the tire changing machine. A more effective use of the two machines could be achieved if the wheel balancer provided an additional means for correcting detected vibration issues in the wheel assembly which are traditionally corrected only by re-mounting of the tire on the wheel rim using the tire changing machine.
Vibration issues in a wheel assembly with a newly mounted tire may arise from tire mounting issues that are no fault of the tire changing machine or a technician operating it. Specifically, in some instances, air can inadvertently become trapped between the tire bead and the wheel rim as a tire is mounted. Similarly, lubrication materials and the like can also inadvertently become trapped between the tire bead and the wheel rim. Either way, this can result in an uneven seating of the tire bead on the periphery of the wheel rim, resulting in vibrations of the wheel assembly that are is not easily amenable to correction other than by releasing the tire and remounting in an attempt to achieve an even or uniform seating of the tire bead to the wheel rim.
Because it is difficult to control conditions that may result in uneven seating of the tire bead on the wheel rim, and further because this occurrence is relatively unpredictable, trial and error is inevitable in attempting to correct a vibration issue attributable to this cause. A technician may attempt to correct the vibration issue on the wheel balancer by applying, removing, or altering imbalance correction weights, only to find the attempts unsuccessful. In this situation, the technician may believe that there is a problem with the wheel balancer or that a mistake was made. Because the uneven bead seating cannot be redressed by a conventional wheel balancer, however, such attempts will be unfruitful. The technician may at some point return to the tire changer to remount the replacement tire, or alternatively may abandon the replacement tire as defective, and install a second replacement tire on the wheel rim. Of course, this is frustrating to the technician, and to the vehicle owner, as the time needed to complete the tire installation becomes extended, sometimes greatly.
Accordingly, it would be beneficial to provide a wheel balancer with additional mechanisms for correcting vibration issues in a wheel assembly, and in particular, with mechanisms for correcting vibration issues caused by uneven bead seating and/or non-uniformity in a tire mounted to a wheel rim.